average (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.
biology The study of living things. The scientists who study them are known as biologists.
calorie The amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. It is typically used as a measurement of the energy contained in some defined amount of food.
carbohydrates Any of a large group of compounds occurring in foods and living tissues, including sugars, starch and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down in an animal’s body to release energy.
chronic A condition, such as an illness (or its symptoms, including pain), that lasts for a long time.
circadian rhythm Biological functions such as body temperature and sleeping/waking times that operate on a roughly 24-hour cycle.
circulation (adj. circulatory) A term that refers to the pumping of some fluid repeatedly throughout a system of vessels. (in medicine) The pumping of blood through the arteries and smaller types of vessels (and from there into other organs and tissues).
colleague Someone who works with another; a co-worker or team member.
constant Continuous or uninterrupted.
fat A natural oily or greasy substance occurring in plants and in animal bodies, especially when deposited as a layer under the skin or around certain organs. Fat’s primary role is as an energy reserve. Fat also is a vital nutrient, though it can be harmful if consumed in excessive amounts.
fuel Any material that will release energy during a controlled chemical or nuclear reaction.
metabolism (adj. metabolic) The set of life-sustaining chemical reactions that take place inside cells and bigger structures, such as organs. These reactions enable organisms to grow, reproduce, move and otherwise respond to their environments.
neuroscientist Someone who studies the structure or function of the brain and other parts of the nervous system.